Threading-tool for automatic machines.



H. T. WHITE.

.THREADING TOOL FOR AUTOMATIC MACHINES- APPLICATION FILED AUG-27,1917- 1,281,4=55. Q Patented 0015. 15, 1918.

2 SHEETSSHEET I.

)WWW A TTORNEYS Ya: mum; versus an. PNc'ra-Lrrnu" wwmuamu, u c,

H. T. WHITE.

THREADING TOOL FOR AUTOMATIC MACHINES.

APPLICATION FILED AUG.2I. 19!].

Patented Oct. 15, 1918.

2 SHEETS-SHEET 2.

FIG. Ev

INVENTOR. jam; 7'- Wiz 2-66 A TTORNEYJS T -FI@.

THREADING-TOOL FOR AUTOMATIC MACHINES.

Specification of Letters Patent.

Patented Oct. 15, 1918.

Application filed August 27, 1917. Serial N 0. 188,422.

To all whom it may concern:

Be it known-that I, HARRY T. WHITE, a citizen of the United States of America, residing at Detroit, in the county of Wayne and State of Michigan, have invented certain new and useful Improvements in Threading- Tools for Automatic Machines, of which the following is a specification, reference being bad therein to the accompanying drawings.

The invention .relates to threading tools of that type in which a collapsible tap or die is engaged with the work-and on completion of the threading-operation is automatically released therefrom. In the present state of the art tools of this character have been devised comprising a head carrying, a series of radially. adjustable jaws to which the cooperating sections of the threading tools or chasers .are secured. Means is also provided for moving the jaws correspondingly from a working to a work-releasing position, and the release is effected automatically by stored power and a trip operated upon the completion of the work.

The accuracy of the work is dependent upon the accuracy of movement of the chasers and this in turn is dependent upon the accuracy of the guides. Usually the chaser-blocks are mounted on a T-shaped jaw member which slidably engages a correspondingly-shaped groove in the head of thetool, but such constructions are open to various objections. In the first place, it is difiicult with such a construction to obtain the accuracy required for good work; and second, it is practically impossible to form hardened bearing surfaces, and consequently the wear incident to use soon renders the tool inaccurate.

It is the object of the present invention to eliminate these defects, first, by a construction which can be easily manufactured and with a high degree of accuracy; and second, by forming the structure of hardened metal which is ground to exact size. To this end the invention comprises the novel construction permitting of such manufacture as hereinafter set forth.

In the drawings: 7

Figure 1 is a sectional elevation of the tool;

Figs. 2 and 3 are cross-sections on line 227Fig. 1, showing the parts in different positions of adjustment; I

Fig. A is an elevation of the cam, showing the engagement of the jaw member there- With;

Figs. 5 andB are cross-sections on line 55 Fig. 4:, showing respectively the workengaging and releasing positions of adjustment.

' A is a head which, as shown, is separate from the shank B and is. secured thereto by set-screws C. D is an auxiliary head telescopically engaging the head A to be longitudinally movable thereof but rotatively fixed thereto. As shown, the head A has an annular portion A within which a cylindrical portion D of the head D fits. E are headedscrews passing through apertures in the end of the head A and engaging the por tion D of the head D, and F are springs surrounding the screws E in a counterbore in the head A, one end of said springs abutting against'the head on-the screw and the other against the shoulder of the counterbore. Thus the heads A and B are held from relative rotative movement, whilethe springs F yieldably hold the same from longitudinal movement.

The auxiliary head D is provided with a portion D of larger diameter than the portion D'and separated from the portion A of the head A to form an annular groove therebetween. In this annular groove is arranged an annular cam member G, the cam H thereof being arrangedon the outer sidea-ndbeing located in a groove I in the portion D of the head D. J are radial boxes in the head D, which intersect the groove I. K are radial slots of lesser width than the diameter of the bores J and extending therefrom outward through theend of the head D. The bores J receive cylindrical blocks or jaw members L, to Which are attached the chaser-blocks M, which latter are of a width to fit the radial slots K. The joint between the chaser-blocks and the jaws L'is formed by a slot L in the jaw for receiving the inner edge of the chaser- .block, and a clamping bolt N, together with the dowel pin 0, serves to hold the parts in fixed relation. The blocksL (Fig. 5) are also provided on their. inner sides with grooves P for engaging the cams H on the annular cam member G.

The construction as thus far described is one which permits of forming the blocks L as Well as the chaser-blocks M of hardened metal, and the head D in which the bores struction T-shaped slots were used. The blocks L- are easily ground to fit the slotsv K. Thus accuracy in construction is ob tained.

The position of the chaser-blocks is. determined by the rotative adjustment'of'the cam G, and to secure accuracy in this adjustment I employ the following construction: Q is a latch-pin slidably mounted in the head A and adapted to engage a socket R in the cam G to lock the chaser-blocks in their working positions of adjustment. The socket R is adjustable in relation to the cam G by being placed in an elongated aperture S in said cam and held in the desired position of adjustment by opposed set-screws S and S Thus by adjusting these setscrews the locking position of the cam may be altered to obtain a predetermined position of adjustment of the chaser-blocks. The locking-pin Q is formed with a collar Q thereon which fits the bore in the head A. A spring T is sleeved upon the shank of the pin between this collar and a bushing T having a threaded engagement with the bore, said bushing performing the double function of a spring abutment and a guide for the pin. Thus the tension of the spring will yieldably torcethe pin Q, outward so that the instant that the socket R comes in registration therewith the pin will snapinto engagement. The pin may, however,

be disengaged by a relative longitudinal movement of the heads A and D, and when so disengaged the cam G will be free for rotative adjustment, which will move the blocks L and chaser-blocks M so as to dis engage the latter from the completed work.

It is desirable to provide means for automatically actuating the cam to its releasing position, and this can be accomplished by a spring,-but as heretofore constructed the assembly of the parts with the spring is a diflicult operation. I have avoided the difiiculty by placing the spring in an open segmental groove in the cam member G and retaining it in this position by a sleeve member which may be longitudinally adjusted upon the heads A. and D. As shown in detail in Fig.2, U is the segmental slot in the cam member GyV is an abutment block fitting within the slot U and secured to the portion D of the head D by bolts V W is a spring which is of segmental form to fit within the slot U, the ends being provided with hearing blocks W respectively bearing against the block V and the opposite end of the slot U; K is a sleeve for fitting over the heads A and D and forming a cover tor the groove U and Y is a handle for manually rotating the cam to set the same in operative position, said handle passing through an aperture in the sleeve X and serving to hold the same in position to cover the slot. V

Theconstruction described is one which can be easily manufactured with a high de gree of accuracy. It is also a simple construction to assemble and the fact that all ofthe parts subject to wear are formed of hardened metal Will greatly increase the life as well as maintain the accuracy of the construction. In use, the chaser-blocks are adjusted to operative position'by manually rotating the cam G through the handle Y until the locking pin Q snaps into engagement with the socket member R. In this position the threading operation .is performed upon. the work,.the head A being drawn longitudinally so asto compensate for the spiral pitch of the thread. At the completion of'the machining operation, a stop (not shown) arrests further longitudinal movement of the head A, whereupon the head Djis drawn away from the head A against the tension of the springs F, and this movement will also disengage the pin Q from the socket R, whereupon the spring W Will quickly rotate the cam to its initial position thereby releasing the chaser-block from the work.

What I claim as my invention is:

1. In a threading tool, the combination of a head having a series of'radially-arranged apertures therein each comprising a slot-portion having parallel sides and a cylindrical portion of greater diameter, said head having a groovetherein which intersects said cylindrical aperture, chaser-blocks fitting said slots having'parallel walls, cylindrical guide-blocks fitting said cylindrical apertures and rigidly secured to I said chaserblocks, a rotary cam fitting the groove and having portions engagingbearings on said cylindrical blocksto simultaneously actuate the same toward and from the axis of the head, a lock for holding said cam in one position of its adjustment, and a spring for actuating said cam rotatively when released from said lock. 7 g

2. In a threading tool, "the combination with a head, of a series of chaser-blocks engaging radial guide hearings in said head,

a rotary cam for actuating said chaserblocks in their radial bearings, a spring for actuating said cam rotatively, located in a peripheral groove in said head,and a sleeve on said head for covering said groove and retaining said spring.

3. In a threading tool, the combination with a head and radially-movable chasers mounted therein, of arotary cam member for operating said chasers engaging a peripheral groove in said head, said rotary member being itself peripherally slotted, an abutment in the peripheral slot of said rotary member secured to said head, a spring arranged between said abutment and the end of the slot in said rotary member, and a sleeve surrounding said head forming a cover for the slot and a retainer for said spring.

4. In a threading tool, the combination with a head and a series of radially-adjustable ohaser-blocks therein, of a rotary cam member for actuating said chaser-blocks, engaging a peripheral groove in said head, a sprlng for actuating said cam member also located in said groove and peripherally insertible therein, and a sleeve surrounding said rotary cam member forming a cover for said groove and a retainer for said spring.

In testimony whereof I affix my signature,

HARRY T. WHITE.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. G. 

